CN112779198B - A kind of method for improving L-histidine production - Google Patents

Abstract

The invention relates to a method for improving L-histidine yield. According to the invention, an ARTP mutagenesis method with safe, mild and strong controllability is used to obtain a mutation library with higher mutation rate, L-histidine structural analogue screening is combined, a stable L-histidine high-yield mutant strain is obtained after ten passages, the mutation condition of L-histidine synthesis related genes of a mutagenized high-yield strain is further analyzed, 5-phosphoribosyl-1-pyrophosphoric acid synthesis related gene Prs and an ATP transphosphoribosyl enzyme coding gene hisG mutant which can promote the L-histidine yield to be improved are obtained through comparison screening, and one or two of the Prs and hisG genes are expressed in a host bacterium for producing L-histidine, so that the L-histidine yield can be effectively improved. Lays a foundation for further metabolic engineering transformation of the serratia marcescens or other strains to produce the L-histidine.

Description

A kind of method for improving L-histidine production

technical field

The invention relates to the technical field of metabolic engineering, in particular to a method for improving the production of L-histidine.

Background technique

L-histidine, also known as α-amino-β-imidazolyl propionic acid, is a basic amino acid containing an imidazole nucleus in the molecule. In the field of nutrition, histidine is considered an essential amino acid for infants and young children. L-histidine has a variety of physiological functions, and plays an important role in growth, tissue repair, and the treatment of ulcers and hyperacidity. It can also be used as an additive for the treatment of allergies, rheumatoid arthritis, and anemia. It is widely used in pharmaceutical and food industries.

The methods of producing histidine mainly include proteolysis, chemical synthesis and microbial fermentation. Among them, hydrolyzed protein is the most traditional method for histidine production. However, this method mainly depends on the availability of natural protein-rich resources (such as blood meal or soybean), and it is difficult to meet the growing demand for histidine; The production of histidine by chemical synthesis tends to produce a racemic mixture, which is generally considered to be a "non-natural" compound, which is difficult to obtain approval from the Food and Drug Administration and is difficult to be accepted by consumers; - The mainstream method of histidine, so the breeding of L-histidine high-producing bacteria has become a current research hotspot.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned technical problems, the present invention provides a method for improving the production of L-histidine. By using the ARTP mutagenesis method with safe, mild and controllable operating conditions, a mutation library with a higher mutation rate is obtained, Combined with the screening of L-histidine structural analogs, after ten passages, a stable L-histidine high-yielding mutant was obtained, and the mutation of L-histidine synthesis-related genes in the high-yield strain after mutagenesis was further analyzed. , the mutated genes that can promote the production of L-histidine were obtained by comparison and screening.

The first object of the present invention is to provide a method for improving the production of L-histidine by expressing the 5-phosphoribose-1-pyrophosphate synthesis gene Prs and /or ATP phosphoribosylase encoding gene hisG, the amino acid sequence of the 5-phosphoribose-1-pyrophosphate synthesis gene Prs is shown in SEQ ID NO.1, and the amino acid sequence of the ATP phosphoribosylase encoding gene hisG The sequence is shown in SEQ ID NO.3.

Further, the L-histidine-producing host bacteria are Enterobacteriaceae strains.

Further, the Enterobacteriaceae strain is Escherichia coli or Serratia marcescens.

Further, the Escherichia coli is E.coli BL21.

Further, the expression of the 5-phosphoribose-1-pyrophosphate synthesis gene Prs and/or the ATP phosphoribosylase encoding gene hisG is expressed through plasmid expression or genome expression.

Further, the plasmid expression is to connect the 5-phosphoribose-1-pyrophosphate synthesis gene Prs or the ATP phosphoribosylase encoding gene hisG to the pET28a carrier for expression; or to express the 5-phosphoribose-1 - The pyrophosphate synthesis gene Prs and the ATP-phosphoribosylase encoding gene hisG are simultaneously connected to the pETDuet vector for expression.

The second object of the present invention is to provide a recombinant bacterium with improved L-histidine production, the recombinant bacterium expresses the 5-phosphoribose-1-pyrophosphate synthesis gene Prs and/or ATP phosphoribosyltransferase Encoding gene hisG, the amino acid sequence of described 5-phosphoribose-1-pyrophosphate synthesis gene Prs is shown in SEQ ID NO.1, and the amino acid sequence of ATP phosphorylation ribosylase encoding gene hisG is shown in SEQ ID NO.3 Show.

Further, the recombinant bacteria use Escherichia coli or Serratia marcescens as the host bacteria, and use pET28a or pETDuet as the carrier.

The third object of the present invention is to provide a method for producing L-histidine by fermentation of the recombinant bacteria, which is to inoculate the recombinant bacteria into a fermentation medium and culture at 28-32°C.

Further, the fermentation medium is glucose 35-45 g/L, yeast powder 1-3 g/L, (NH ₄ ) ₂ SO ₄ 14-18 g/L, K ₂ HPO ₄ .3H ₂ O 0.5-0.7 g /L, FeSO ₄ .7H ₂ O 0.004～0.006g/L, MnSO ₄ .5H ₂ O 0.004～0.006g/L, CaCO ₃ 25～35g/L.

By means of the above scheme, the present invention has at least the following advantages:

The invention obtains a mutation library with a higher mutation rate by using the ARTP mutagenesis method with safe, mild and controllable operating conditions. Combined with the screening of L-histidine structural analogs, after ten passages, a stable The L-histidine high-yielding mutant strain was further analyzed, and the mutation of L-histidine synthesis-related genes in the high-yielding strain after mutagenesis was further analyzed, and the 5-phosphoribose- 1-pyrophosphate synthesis gene Prs and L-histidine synthesis operon gene hisG mutant, expressing one or both of Prs and hisG genes in L-histidine-producing host bacteria, can effectively increase L-histidine - Production of histidine. It lays a foundation for further metabolic engineering of Serratia marcescens or other strains to produce L-histidine.

The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly and implement it according to the content of the description, the following description is given with the preferred embodiments of the present invention and the detailed drawings.

Description of drawings

Figure 1 shows the lethality curve of ARTP to S. marcescens ATCC 31026;

Fig. 2 is the screening result of 6-MP resistant mutant strain;

Fig. 3 is the genetic stability of L-histidine-producing strain S. marcescens P12;

Fig. 4 is the sequence alignment of the Prs gene of S. marcescens P12 and S. marcescens ATCC 31026;

Fig. 5 is the sequence alignment of the hisG gene of S. marcescens P12 and S. marcescens ATCC 31026;

Figure 6 is the L-histidine production of hisG gene before and after expressing mutagenesis in E. coli BL21 respectively;

Figure 7 is the L-histidine production of the Prs gene before and after expressing mutagenesis in E. coli BL21 respectively;

Figure 8 shows the L-histidine production of Prs and hisG genes in E. coli BL21 before and after mutagenesis, respectively.

Detailed ways

The specific embodiments of the present invention will be further described in detail below with reference to the examples. The following examples are intended to illustrate the present invention, but not to limit the scope of the present invention.

In the present invention, the base sequence of the 5-phosphoribose-1-pyrophosphate synthesis gene Prs before mutation is shown in SEQ ID NO.6, the amino acid sequence is shown in SEQ ID NO.2, and the base sequence after mutation is shown in SEQ ID NO.2 ID NO.5 is shown, and the amino acid sequence is shown as SEQ ID NO.1;

The base sequence before the mutation of the ATP phosphoribosylase encoding gene hisG is shown in SEQ ID NO.8, the amino acid sequence is shown in SEQ ID NO.4, and the base sequence after the mutation is shown in SEQ ID NO.7, The amino acid sequence is shown in SEQ ID NO.3.

The concentration of L-histidine in the fermentation broth was quantitatively analyzed by high performance liquid chromatography (HPLC). The fermentation broth was derivatized before column with o-phthalaldehyde. The chromatographic column was an Agilent C18 column (250mm×4.6mm, 5μm). The detection wavelength of the UV detector was 338 nm, the column temperature was 40 °C, and the injection volume was 1 μL. The specific gradient elution procedure is shown in the table below.

Table 1

Example 1: Determination of the critical lethal 6-MP concentration of S. marcescens ATCC 31026

A single colony of S. marcescens ATCC 31026 before mutagenesis was inoculated into 2mL LB medium (yeast powder 5g/L, tryptone 10g/L, NaCl 10g/L), 37°C, 220r/min, cultured for 10-12h, Centrifuge the bacteria, wash 2-3 times with sterile physiological saline, then dilute 100,000-fold gradient with sterile physiological saline, and then take 100 μL of the bacterial solution and apply it to 6-MP containing 1.5 mg/mL MET and different concentrations. Resistant plates (glucose 5.0g/L, beef extract 10g/L, peptone 10g/L, yeast extract 5.0g/L, sodium chloride 2.5g/L, agar 20g/L, pH adjusted to 7.0, sterilized at 121°C bacteria for 15 min), the critical lethal concentration of 6-MP was determined to be 1.5 mg/mL, so 1.5 mg/mL was selected as the experimental concentration. As shown in table 2.

Table 2

Note: ++ means more single colonies; + means few single colonies; - means no single colonies

Example 2: Mutagenesis of S. marcescens ATCC 31026 using ARTP

Select S. marcescens ATCC 31026 for ARTP mutagenesis. The first step is to prepare a bacterial suspension. A single colony of S. marcescens ATCC 31026 is placed in LB medium to a 14 mL shaker tube at 37°C, 220 r/min. After overnight culture, the inoculum is 1%. Transfer to LB shake flask, 37 ℃, 220r/min, cultivate 4-6h. The cultured cells were collected by centrifugation, washed 2-3 times with sterile physiological saline, and then diluted with sterile physiological saline to form a bacterial suspension with an OD ₆₀₀ value of 0.6-0.8, and 10 μL of the bacterial suspension was spread on a glass slide. deal with. The parameters of ARTP mutagenesis are as follows: the slide is at 2mm of the airflow port, the power is 120W, the airflow rate is 10SLM, and the action time is 35s.

The ARTP mutagenized bacterial suspension was spread on MET (1.5 mg/mL) and 6-MP (1.5 mg/mL) resistant plates, and after culturing at 30°C for 36 hours, thirty single colonies were obtained.

Example 3: Fermentative synthesis of L-histidine

Pick a single colony of the obtained 30 mutant strains of S. marcescens P1--30 and inoculate it into a 500mL conical flask, the filling volume is 500mL, 30℃, 220r/min, cultured for 18h, the formula of the seed medium It is: glucose 25g/L, corn steep liquor 20g/L, urea 1.25g/L, potassium dihydrogen phosphate 1.0g/L, magnesium sulfate 0.5g/L, pH adjusted to 7.0, sterilized at 121°C for 15min, glucose was sterilized separately Bacteria (115°C, 15min); pipette 1.5mL of seed medium at 10% of the inoculum into a 250mL conical flask, fill 15mL, 30°C, 220r/min, cultivate for 72h, the formula of the fermentation medium is: glucose 130g/L, ammonium sulfate 35g/L, corn steep liquor 15g/L, potassium dihydrogen phosphate 1.0g/L, magnesium sulfate 0.5g/L, calcium carbonate 20g/L (dissolved), pH adjusted to 7.0, sterilized at 115°C bacteria, 15min.

The L-histidine production in the supernatant of the fermentation broth was analyzed by liquid phase, and four high-yielding strains were obtained, such as S. Among these mutants, the mutant S. marcescens P12 with the highest L-histidine production was selected for subculture, as shown in Figure 3. The results showed that the cells grew well, with an average acid production of 5.3 g/L, and a stable and high-yielding mutant was obtained. , for further research.

Example 4: Amplification and alignment of genes related to L-histidine synthesis

The primers shown in Table 1 were designed according to S. marcescens ATCC 31026 measured in the present invention. Using the above primers and S. marcescens P12 genome as a template, the Prs gene and hisLGDCBHAFI gene clusters were amplified by PCR, and the fragment lengths were 939 bp and 7287 bp, respectively. The amplified fragments were compared with the corresponding genes of S. marcescens ATCC 31026, and it was found that both Prs and hisG genes had amino acid mutations, as shown in Figure 4 and Figure 5.

table 3

Example 5: Construction and transformation of Prs and hisG related plasmids

In order to verify whether the mutated genes Prs and hisG in the present invention can increase L-histidine production in Escherichia coli, plasmids pET28a-Prs and pET28a-hisG were constructed using the Prs and hisG genes before the mutation, and the mutated Prs and hisG genes were used to construct plasmids pET28a-Prs and pET28a-hisG. HisG gene constructs plasmids pET28a-Prs', pET28a-hisG'. Using the genome of S. marcescens ATCC 3102, S. marcescens P12 and pET28a plasmid as templates, using primers in Table 4, the sequences of hisG, hisG', Prs, Prs' and corresponding linearized plasmids were obtained through PCR amplification, and further Recombinant plasmids pET28a-hisG, pET28a-hisG', pET28a-Prs, pET28a-Prs' were obtained by Gibson assembly. After heat shock at 42°C for 90s, they were transformed into E.coli BL21 competent cells to obtain strain E.coli B1, E.coli B2, E.coli B3, E.coli B4.

Table 4

Example 6: Escherichia coli fermentation to synthesize L-histidine

Single colonies of strains E.coli B1, E.coli B2, E.coli B3 and E.coli B4 were picked and inoculated into 2mL liquid LB medium (yeast powder 5g/L, tryptone 10g/L, NaCl 10g/L) medium, cultured overnight at 37°C and 220 r/min. At 4% (V/V), the seed liquid was inoculated into 15mL fermentation medium (glucose 40g/L, yeast powder 2g/L, (NH ₄ ) ₂ SO ₄ 16g/L, K ₂ HPO ₄ .3H ₂ O 0.6 g/L, FeSO ₄ .7H ₂ O 0.005g/L, MnSO ₄ .5H ₂ O 0.005g/L, CaCO ₃ 30g/L) in a 250mL shaker flask, cultured at 30°C, 220r/min for 72h. The production of L-histidine in the supernatant of the fermentation broth was analyzed by liquid phase, and the results are shown in FIG. 6 and FIG. 7 . The fermentation results showed that the yield of hisG sequence before mutagenesis was 0.2g/L in E.coli BL21, while the yield of hisG sequence after mutagenesis could be increased to 1.5g/L; when expressed in E.coli BL21 The yield of the Prs sequence before mutagenesis was 0.4 g/L, while the expression of the hisG sequence after mutagenesis could increase the yield to 1 g/L.

Example 7: Construction and transformation of Prs and hisG double gene expression plasmids

In order to verify whether the co-expression of the mutated genes Prs and hisG in the present invention in Escherichia coli can further improve the L-histidine production, the plasmid pETDuet-Prs-hisG was constructed using the Prs and hisG genes before the mutation, and the mutated Prs was used to construct a plasmid pETDuet-Prs-hisG. and hisG gene to construct plasmid pETDuet-Prs'-hisG'. Taking the genome of S. marcescens ATCC 3102 and S. marcescens P12 and the pETDuet plasmid as templates, using the primers in Table 5, the sequences of hisG, Prs, hisG', Prs' and the corresponding linearized plasmids were obtained by PCR amplification, and further passed through The recombinant plasmids pETDuet-Prs-hisG and pETDuet-Prs'-hisG' were obtained by Gibson assembly. After heat shock at 42°C for 90s, they were transformed into E.coli BL21 competent cells to obtain strains E.coli B5, E.coli B6.

table 5

Example 8: Escherichia coli fermentation to synthesize L-histidine

Single colonies of strains E.coli B5 and E.coli B6 were picked and inoculated in 2mL liquid LB medium (5g/L yeast powder, 10g/L tryptone, 10g/L NaCl), and cultured overnight at 37°C and 220r/min. . At 4% (V/V), the seed liquid was inoculated into 15mL fermentation medium (glucose 40g/L, yeast powder 2g/L, (NH ₄ ) ₂ SO ₄ 16g/L, K ₂ HPO ₄ .3H ₂ O 0.6 g/L, FeSO ₄ .7H ₂ O 0.005g/L, MnSO ₄ .5H ₂ O 0.005g/L, CaCO ₃ 30g/L) in a 250mL shaker flask, cultured at 30°C, 220r/min for 72h. The production of L-histidine in the supernatant of the fermentation broth was analyzed by liquid phase, and the results are shown in FIG. 8 . The fermentation results showed that the yield of Prs and hisG sequences before mutagenesis was simultaneously expressed in E. coliBL21, and the yield was 1.2 g/L, while the yield of Prs and hisG sequences after mutagenesis could be increased to 3.5 g/L.

The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. It should be pointed out that for those skilled in the art, some improvements and modifications can be made without departing from the technical principles of the present invention. , these improvements and modifications should also be regarded as the protection scope of the present invention.

sequence listing

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tcccaggaat tgctggcgcg ctgcggcatc aagattaacc tgcagcagca gcgtctgatc 120

gccttcgccg aaaacatgcc gatcgatatc ctgcgcgtgc gcgacgacga cattccgggt 180

ctggtgatgg acggcgtggt cgatctcggc atcatcggcg agaacgtgct ggaagaagag 240

ctgctcagcc gccgcgcaca gggtgaagac ccgcgctact tcaccctgcg ccgcctcgat 300

ttcggcggct gccgcctgtc gctggccacc ccgctcgacg ccgaatacgc cggcccgcaa 360

agcctgcagg acgcccgcat cgccacttct tacccgcacc tgctgaagca atacctcgac 420

aaacagggcg tgcgcttcaa atcttacctg ctgaacggct cggtggaagt ggcgccgcgc 480

gccggcctgg ccgacgccat ctgcgatctg gtctctaccg gcgccacgct ggaggccaac 540

ggcctgcgcg aagtggaggt gatctaccgc tccaaagctt gcctgatcca gcgcgacggc 600

gaaatgcctg aagccaaaca gcagctgatt gaccgcctga tgacccgcat tcagggcgtg 660

atccaggcgc gcgaatccaa atacatcatg ctgcacgcgc cgagcgagaa actggatgag 720

atcgtcgcgc tgctgccggg cgccgaacgc ccgaccattc tgccgctggc cggtgcgcag 780

aaccgcgtgg cgatgcacat ggtcagcagc gaaaccctgt tctgggaaac catggaaaaa 840

ctgaaagcgc tcggcgccag ctcgattctg gtgctgccga ttgaaaagat gatggagtaa 900

<210> 8

<211> 900

<212> DNA

<213> (artificial sequence)

<400> 8

atgctggaca agacacgttt acggatcgca atgcagaagt cgggccgcct gagcgatgaa 60

tcccaggaac tgctggcacg ctgcggcatc aagatcaacc tgcagcagca gcgtctgatc 120

gccttcgccg aaaacatgcc gatcgatatc ctgcgcgtgc gcgacgacga catcccgggc 180

ctggtgatgg acggcgtggt cgatctcggc atcatcggcg agaacgtgct ggaagaagag 240

ctgctcagcc gccgcgccca gggtgaagac ccgcgttact tcaccctgcg ccgcctcgat 300

ttcggcggct gccgcctgtc gctggccacc ccgctcgacg ccgaatacgc cggcccgcaa 360

agcctgcagg acgcccgcat cgccacctct tatccgcacc tgctgaagca atacctcgac 420

aaacaaggcg tgcgcttcaa atcttgcctg ctgaacggct cggtggaagt cgcgccgcgc 480

gccggcctgg ccgacgccat ctgcgatctg gtctctaccg gcgccacgct ggaggccaac 540

ggcctgcgcg aagtggaggt gatctaccgc tccaaagctt gcttgatcca gcgcgacggc 600

gaaatgcctg aagccaaaca gcagctgatt gaccgcctga tgacccgcat tcagggcgtg 660

atccaggcgc gcgaatccaa atacatcatg ctgcacgcgc cgagcgagaa gctggacgag 720

atcgtcgcgc tgctgccggg cgccgaacgc ccgaccattc tgccgctggc cggcgcgcag 780

aatcgcgtgg cgatgcacat ggtcagcagc gaaaccctgt tctgggaaac catggaaaaa 840

ctgaaagcgc tcggcgccag ctcgattctg gtgctgccga ttgaaaagat gatggagtaa 900

<210> 9

<211> 24

<212> DNA

<213> (artificial sequence)

<400> 9

atgaagcttt ttgctggtaa cgcc 24

<210> 10

<211> 25

<212> DNA

<213> (artificial sequence)

<400> 10

tcaatgctcg aacatcgcag agatc 25

<210> 11

<211> 22

<212> DNA

<213> (artificial sequence)

<400> 11

atgacacgcg ttcagttcaa cc 22

<210> 12

<211> 22

<212> DNA

<213> (artificial sequence)

<400> 12

tcacgctttt ttctgatgcc gc 22

<210> 13

<211> 23

<212> DNA

<213> (artificial sequence)

<400> 13

ggcagcagcc atcatcatca tca 23

<210> 14

<211> 45

<212> DNA

<213> (artificial sequence)

<400> 14

ggtatatctc cttcttaaag ttaaacaaaa ttatttctag agggg 45

<210> 15

<211> 43

<212> DNA

<213> (artificial sequence)

<400> 15

ctttaagaag gagatatacc atgctggaca agacacgttt acg 43

<210> 16

<211> 49

<212> DNA

<213> (artificial sequence)

<400> 16

tgatgatgat ggctgctgcc ttactccatc atcttttcaa tcggcagca 49

<210> 17

<211> 45

<212> DNA

<213> (artificial sequence)

<400> 17

ctttaagaag gagatatacc atgaagcttt ttgctggtaa cgcca 45

<210> 18

<211> 44

<212> DNA

<213> (artificial sequence)

<400> 18

tgatgatgat ggctgctgcc tcaatgctcg aacatcgcag agat 44

<210> 19

<211> 21

<212> DNA

<213> (artificial sequence)

<400> 19

ttaacctagg ctgctgccac c 21

<210> 20

<211> 44

<212> DNA

<213> (artificial sequence)

<400> 20

ggtatatctc cttcttaaag ttaaacaaaa ttatttctag aggg 44

<210> 21

<211> 44

<212> DNA

<213> (artificial sequence)

<400> 21

ctttaagaag gagatatacc atgaagcttt ttgctggtaa cgcc 44

<210> 22

<211> 23

<212> DNA

<213> (artificial sequence)

<400> 22

tcaatgctcg aacatcgcag aga 23

<210> 23

<211> 51

<212> DNA

<213> (artificial sequence)

<400> 23

tgcgatgttc gagcattgat gcttaagtcg aacagaaagt aatcgtattg t 51

<210> 24

<211> 44

<212> DNA

<213> (artificial sequence)

<400> 24

atgtatatct ccttcttata cttaactaat atactaagat gggg 44

<210> 25

<211> 43

<212> DNA

<213> (artificial sequence)

<400> 25

tataagaagg agatatacat atgctggaca agacacgttt acg 43

<210> 26

<211> 47

<212> DNA

<213> (artificial sequence)

<400> 26

ggcagcagcc taggttaatt actccatcat cttttcaatc ggcagca 47

Claims (10)

1. A method for improving the yield of L-histidine is characterized in that 5-phosphoribosyl-1-pyrophosphate synthesis gene Prs and/or ATP-phosphoribosyl-transferase coding gene hisG are expressed in a host bacterium for producing L-histidine, the amino acid sequence of the 5-phosphoribosyl-1-pyrophosphate synthesis gene Prs is shown as SEQ ID NO.1, and the amino acid sequence of the ATP-phosphoribosyl-transferase coding gene hisG is shown as SEQ ID NO. 3.

2. The method of claim 1, wherein the L-histidine-producing host bacterium is a strain of the family enterobacteriaceae.

3. The method of claim 2, wherein the Enterobacteriaceae strain is Escherichia coli or Serratia marcescens.

4. The method of claim 3, wherein the Escherichia coli is E.coli BL21.

5. The method according to claim 1, wherein the expression of the 5-phosphoribosyl-1-pyrophosphate synthesis gene Prs and/or the ATP-transphosphoribosylase encoding gene hisG is by plasmid expression or genomic expression.

6. The method of claim 5, wherein the plasmid expression is performed by ligating 5-phosphoribosyl-1-pyrophosphate synthesis gene Prs or ATP phosphoribosyl transferase encoding gene hisG to pET28a vector; or 5-phosphoribosyl-1-pyrophosphate synthesis gene Prs and ATP transphosphoribosyl enzyme coding gene hisG are simultaneously connected to pETDuet vector for expression.

7. A recombinant bacterium with improved L-histidine yield is characterized in that the recombinant bacterium expresses a 5-phosphoribosyl-1-pyrophosphate synthetic gene Prs and/or an ATP-phosphoribosyl transferase coding gene hisG, the amino acid sequence of the 5-phosphoribosyl-1-pyrophosphate synthetic gene Prs is shown as SEQ ID No.1, and the amino acid sequence of the ATP-phosphoribosyl transferase coding gene hisG is shown as SEQ ID No. 3.

8. The recombinant strain of claim 7, wherein the recombinant strain is a host strain selected from Escherichia coli or Serratia marcescens, and the vector is pET28a or pETDuet.

9. A method for producing L-histidine by fermentation of the recombinant bacterium according to claim 7, characterized in that the recombinant bacterium is inoculated into a fermentation medium and cultured at 28-32 ℃.

10. The method of claim 9, wherein the fermentation medium comprises glucose 35-45 g/L, yeast powder 1-3 g/L, (NH) ₄ ) ₂ SO ₄ 14～18g/L，K ₂ HPO ₄ .3H ₂ O 0.5～0.7g/L，FeSO ₄ .7H ₂ O 0.004～0.006g/L，MnSO ₄ .5H ₂ O 0.004～0.006g/L，CaCO ₃ 25～35g/L。

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